<template>
  <span>{{ value }}</span>
</template>
<script lang="ts" setup>
import { ref, computed, onMounted, watch, watchEffect } from 'vue'
import { useTransition, TransitionPresets } from '@vueuse/core'
interface Props {
  /** 初始值 */
  startValue?: number
  /** 结束值 */
  endValue?: number
  /** 动画时长 */
  duration?: number
  /** 自动动画 */
  autoplay?: boolean
  /** 进制 */
  decimals?: number
  /** 前缀 */
  prefix?: string
  /** 后缀 */
  suffix?: string
  /** 分割符号 */
  separator?: string
  /** 小数点 */
  decimal?: string
  /** 使用缓冲动画函数 */
  useEasing?: boolean
  /** 缓冲动画函数类型 */
  transition?: string
}
const props = withDefaults(defineProps<Props>(), {
  startValue: 0,
  endValue: 2021,
  duration: 1500,
  autoplay: true,
  decimals: 0,
  prefix: '',
  suffix: '',
  separator: ',',
  decimal: '.',
  useEasing: true,
  transition: 'linear',
})
const emit = defineEmits<{
  (e: 'on-started'): void
  (e: 'on-finished'): void
}>()
const source = ref(props.startValue)
let outputValue = useTransition(source)
const value = computed(() => formatNumber(outputValue.value))
const disabled = ref(false)
function run() {
  outputValue = useTransition(source, {
    disabled,
    duration: props.duration,
    onStarted: () => emit('on-started'),
    onFinished: () => emit('on-finished'),
    ...(props.useEasing
      ? { transition: TransitionPresets[props.transition] }
      : {}),
  })
}
function start() {
  run()
  source.value = props.endValue
}
function isNumber(data: unknown) {
  return Object.prototype.toString.call(data) === '[object Number]'
}

function formatNumber(num: number | string) {
  if (!num) {
    return ''
  }
  const { decimals, decimal, separator, suffix, prefix } = props
  let number = Number(num).toFixed(decimals)
  number += ''
  const x = number.split('.')
  let x1 = x[0]
  const x2 = x.length > 1 ? decimal + x[1] : ''
  const rgx = /(\d+)(\d{3})/
  if (separator && !isNumber(separator)) {
    while (rgx.test(x1)) {
      x1 = x1.replace(rgx, `$1${separator}$2`)
    }
  }
  return prefix + x1 + x2 + suffix
}
watch([() => props.startValue, () => props.endValue], () => {
  if (props.autoplay) {
    start()
  }
})
watchEffect(() => {
  source.value = props.startValue
})
onMounted(() => {
  if (props.autoplay) {
    start()
  }
})
</script>
